Fuse-plug



W. G. STOESER.

FUSE PLUG.

APPLICATION FILED JUNE 16, m9.

7 Patented June 22, 1920.

wuc/wboz US View Sfiom new UNITED STATES PATENT OFFICE.

WALTER G. STOESER, OF SEATTLE, WASHINGTON, ASSIGNOZR OF ONE-HALF; 1'0 ADOLPH WETSTEIN, 0F 102"LAND, OREGON.

FUSE-PLUG.

Specification of Letters Patent.

Application filed June 18, 1919. Serial No. 304,812.

To all whom it may concern:

Be it known that I, WALTER Gr. S'ronsnn, a citizen of the United States, and residing at Seattle, in the county of King and State of Washington, have invented a. new and Improved Fuse-Plug, of which the following is a. specification.

his invention relates to fuses employed in electric circuits to prevent the passage of undesirably heavy currents and its ob- 'ect is to provide a simple and efficient fuse older and a support wherein the fuse and its holder are mounted, which support comprises a plug having a central cavity to receive the fuse. and holder and a cap to close the cavity, the plug being adapted to be screwed into the usual fuse receptacle, and the cap being freely removable to permit the insertion of a fresh fuse. A. further object of this invention is to provide an opening in the cap through which the fuse may be observed and transparent means to close this opening and to retain the fumes arising from the burning of the fuse.

In the accompai'iyiug drawing. Figure l is an elevation of this improved fuse plug. 1

Fig. 2 is a central longitudinal section thereof. Fig. 3 is a section on the line 23-45 of Fig. 2. Fig. 4 is a plan of the body of the plug. Fig. 5 is a central section of the fuse and its holder. Fig. 6 is a plan of a fuse before it is fitted to its holder.

Similar reference characters refer to Like parts throughout the several views.

This fuse plug is adapted to fit such sockets as have an exterior contact in the form of an internally threaded sleeve and an interior contact in the form of a resilient plate usually central of the bottom of the socket and insulated from the sleeve. For this reason, the body 1 of the present device, which is of porcelain, glass, indurated fiber or any other good non-conductor is formed with a spiral thread which fits and retains the sleeve or ferrule 2 which has been spirally headed to fit the thread on the body. A conductor screw 3 having a flat contact head 4 extends centrally of the body and connects to the fuse contact 5 which is seated in a cavity in the top of the body. A second conductor screw 6 extends along the bottoms of the thread on the body and along in contact with the inner points of the spirel head on the sleeve 2, as shown in Fig. 2, and connects to the other fuse contact 7 which is thereby brought in circuit with this threaded sleeve.

The, upper part of the body is also threaded and receives the screw threaded cap 8 which is preferably of insulating ma.- terial and provided with an opening or window 9 through which the fuse may be observed. The fuse is preferably a thin flat strip 11 of metal which is narrowed at 12" and, if desired, also formed with a hole 13,

the metal remaining being sufficient to carry only the permissible current without melting but being destroyed when excessive current passes over the circuit, which embodies this fuse plug.

The fuse is mounted on a holder consisting of a cross bar 15 and legs 16, around which the fuse is bent, the holder being preferably of indurated fiber or other nonconductor which is not readily affected by the heat generated by the fuse when it blows up. A sheet 17 of mica is placed over the fuse before the cap is screwed down and serves to press the lower ends of the legs 16 and the fuse below them against the fuse contacts 5 and 7 and also to close the opening 9 and thus prevent the escape of the fumes of the burning fuse metal when the fuse blows. The distances between the legs H) of the fuse holder and between the outer faces of the parts 18 and 19 of the use contacts are preferably such that the inturned ends 20 of the fuse will be ressed against these parts 18 and 19 an assist in completely closing the circuit between the head 4 and sleeve 2.

In order to avoid breakage of the body of the plug because of the pressure of the gas resulting from the burning of the fuse, I may provide the passage 22 in the body of the plug and extending up to the-edge of the sheet 17 he details and proportions of the various parts of this device may be changed by those skillc d in the electric arts without departing from the invention set forth in the following claims.

I claim 1. In a fuse plug, the combination of a body having threaded ends and a cavity in one end consisting of a transverse portion and two legs extending longitudinally of the bod a cap screwed onto one end to close sai cavity, a pair of fuse contacts mounted in said cavity and in the longitudinal extensions of said cavity and a fuse holder fitting within said cavity and said contacts, a strip of fuse metal fitting around said holder and pressed into engagement with said fuse contacts within the cavity, a central conductor having a contact end at the end of the body opposite said cap and connecting to one of the fuse contacts, a sleeve fitting around the other threaded end of the body, and means connecting the sleeve to the second fuse contact.

2. In a fuse plug, the combination of a body having a cavity, a cap to close said cavity, a air of contacts on the surface of sand 100 y, a fuse holder mounted in said cavity and comprising a cross bar and legs extending therefrom, a strip of fuse metal fitting against the cross bar around the legs of the fuse holder, a pair of fuse contacts within the cavity, and means connecting the fuse contacts to the contacts on the surface of the body.

3. In a fuse plug, the combination of a body having a cavity, a cap to close said cavit a pair of contacts on the surface of said ody, a fuse holder mounted in said cavity and comprising a cross bar and legs extending therefrom, a strip of fuse metal fitting around the fuse holder, a pair of fuse contacts within the cavity and formed to receive said legs, and means connecting the fuse contacts to the contacts on the surface of the body, said cap being formed with an opening through which the strip of fuse metal may be observed, and a sheet of transparent material mounted across said 0penmg.

4:. In a fuse plug, the combination of a body of non-conducting material having a cavity, a pair of contacts on the surface of said body, a fuse holder removably mounted in said cavity and comprising a cross bar and ':W0 downwardly curtendirn legs, a strip of fuse metal fitted around said holder and the ends thereof, a pair of stationary fuse contacts within the cavity adapted to engage the ends of said strip of fuse metal, conductors between the fuse contacts and the contacts on the surface of said body, and a closure for said cavity.

WALTER G. STOESER. 

